Efforts are ongoing to develop and deploy new and improved cellular radio access technologies (RATs). For example, networks implementing Long Term Evolution (LTE) technology, developed and standardized by the Third Generation Partnership Project (3GPP), are currently being deployed. LTE and other newer RATs often support faster data rates than networks utilizing legacy RATs, such as various second generation (2G) and third generation (3G) RATs.
However, in some deployments, LTE and other new RATs may not fully support some services that can be handled by legacy networks. Accordingly, LTE networks are often co-deployed in overlapping regions with legacy networks and wireless communication devices may transition between RATs as services or coverage may require. For example, in some deployments, LTE networks are not capable of supporting voice calls. Thus, for example when a wireless communication device receives or initiates a circuit switched voice call while connected to an LTE network that supports data sessions, but not voice calls, the wireless communication device can transition to a legacy network, such as Code Division Multiple Access 2000 (CDMA2000) 1X, which is standardized by the Third Generation Partnership Project 2 (3GPP2), that supports voice calls.
Some wireless communication devices use a single radio to support operation on multiple cellular RATs. For example, some wireless communication devices use a single radio to support operation on both LTE and CDMA2000 1X networks. The use of a single radio for multiple RATs makes transitioning between networks, such as in response to a page message for an incoming voice call or circuit switched service, more complex.